Inside Health

Potent Virus Threatens Babies' Breathing

By HOLCOMB B. NOBLE

Published: December 14, 1999

A highly contagious respiratory virus that often overwhelms pediatric clinics in winter has arrived in force, federal officials say, and is sending twice as many babies to the hospital as scientists had expected.

As a result, specialists are urging parents and pediatricians to be especially vigilant for breathing difficulties in babies at risk for the virus: twins and other multiples, whose lungs are generally not as developed at birth as single babies; premature babies; and those born with lung or heart disorders.

Why the virus seems rampant this year is unclear, but pediatricians suspect one important reason may be the rising numbers of babies under 6 months of age in day-care centers. The doctors say these very young children come in frequent contact with other babies who may be infected, or with workers who may touch one child and pass the virus to another.

Commonly known as R.S.V., for respiratory syncytial virus, it infects nearly all young children sooner or later. But normally, its effects are indistinguishable from the common cold and it goes away without harm. In some babies, however, it rapidly penetrates even the smallest inner branches of the lungs' airway systems and may result in inflammations and blockages. And that can cause permanent lung damage and even death if not controlled soon enough.

The federal Centers for Disease Control and Prevention reported in The Journal of the American Medical Association that more than 100,000 hospitalizations a year are related to R.S.V. -- one and a half to two times the expected number. C.D.C. officials think the virus causes about 500 deaths a year.

Dr. Michael Frogel, chief of pediatrics at Schneider Children's Hospital in New Hyde Park, N.Y., calls the current peak season, which generally runs from November through April, one of the worst he has seen. And Dr. Alan H. Cohen, a lung specialist at Morehouse School of Medicine, says it has reached epidemic proportions in the Atlanta area.

Pediatricians advise parents and those who come close to babies at high risk to be doubly certain to wash their hands with warm water before and after touching them, to discourage visits by people with colds and to keep the babies away from crowds. Child-care workers are warned to be alert for wheezing and other breathing problems.

Dr. Cohen offers these warning signs: ''Look for flaring of the nostrils, grunting inability to drink, to hydrate. Take off the shirt. Look at the neck for contracting muscles, for tugging above and at the chest. If belly muscles are tightening with each breath, the child is going into respiratory failure.''

Dr. Frogel said in an interview that many doctors themselves needed to be trained in R.S.V. management and in detecting the virus. Techniques developed over the past few years can quickly determine whether the child has been infected, he said, including methods of discovering antigens in the babies' nasal mucus, and blood monitors that detect whether oxygen levels are high enough.

Pediatricians say there is a highly effective new drug that should be given once a month to all high-risk babies, even though it is expensive, at $1,000 an injection. The drug, palivizumab, whose trade name is Synagis, was approved by the federal Food and Drug Administration last year. Dr. Frogel said that he gave it to 269 high-risk children last year and that so far none have shown symptoms of the infection. Dr. Cohen put 320 on the drug and only 5 became infected.

The medication is a monoclonal antibody, developed artificially by genetic engineering, which acts like an antibody of the human immune system. It lies in wait in a baby's body, then attaches to the invading virus and neutralizes it before it can begin replicating.

But the drug is effective for only a month and is not powerful enough to combat the virus after it has entered the body and proliferates, inflaming the inner airways. ''By that point,'' said Dr. David K. Shay, a pediatrician and epidemiologist with the C.D.C.'s viral division, ''the inflammation has already occurred and it's too late.''

The manufacturer, MedImmune of Gaithersburg, Md., said the drug's high cost reflected extraordinary expenses incurred in genetically engineering and producing it, and in the long clinical trials needed to make certain the drug was safe. Doctors said the costs of treating the children were being covered by most insurance companies and by Medicaid.